1551-88-8Relevant articles and documents
A new route to furanoeremophilane sesquiterpenoids. Synthesis of Senecio metabolites (±)-6-hydroxyeuryopsin, (±)-1,10-epoxy-6- hydroxyeuryopsin, (±)-toluccanolide A and (±)-toluccanolide C
Mace, Laura H.,Shanmugham, M. Sundaram,White, James D.,Drew, Michael G. B.
, p. 1020 - 1031 (2006)
A new strategy for the synthesis of sesquiterpenoids of the furanoeremophilane family was developed in which the tricyclic nucleus was assembled in an A + C → A-C → A-B-C sequence. The A-C connection was made via coupling of a cyclohexenylmethyl bromide with a stannylfuran under "ligandless" Stille conditions, and the key cyclization which closed ring B was accomplished with complete stereocontrol by intramolecular formylation of a 2-silylfuran in the presence of trimethylsilyl triflate. This route was used to complete the first total syntheses of the furanoeremophilane 6-hydroxyeuryopsin and the eremophilenolides toluccanolide A and toluccanolide C, as well as a formal synthesis of 1,10-epoxy-6-hydroxyeuryopsin. The Royal Society of Chemistry 2006.
Stereospecific sp3 C–H oxidation with m-CPBA: A CoIII Schiff base complex as pre-catalyst vs. its CoIIICdII heterometallic derivative
Nesterova, Oksana V.,Kasyanova, Katerina V.,Makhankova, Valeriya G.,Kokozay, Vladimir N.,Vassilyeva, Olga Yu.,Skelton, Brian W.,Nesterov, Dmytro S.,Pombeiro, Armando J.L.
, p. 171 - 184 (2018/05/28)
The mono- and binuclear Schiff base complexes [CoL3]·DMF (1) and [CoCdL3Cl2]·0.5H2O (2) were facilely synthesized using zerovalent cobalt and cadmium chloride (for 2) as starting materials and the pre-formed pro-ligand HL (2-methoxy-6-[(methylimino)methyl]phenol, the product of condensation of o-vanillin and methylamine) in air. The compounds were characterized by single crystal X-ray diffraction analysis and spectroscopic methods in solution and in the solid state. Both complexes demonstrate a profound catalytic activity in the stereoselective oxidation of cis-1,2-dimethylcyclohexane (model substrate) with m-CPBA (m-chloroperbenzoic acid) under mild conditions in the presence of promoters of various acidity (HNO3, TFA and HOAc). The heterometallic binuclear CoIIICdII pre-catalyst (2) was more active than the mononuclear CoIII one (1), exhibiting higher products yields up to 51% and excellent stereospecificity (up to 99.2% retention of stereoconfiguration). This result could be associated with a synergistic effect of two different metals in 2. Based on the large obtained kinetic isotope effect and H218O labeling studies, the overall reaction mechanism was proposed to proceed without the participation of free alkyl radicals. The acidity of the promoter was shown to influence catalytic parameters for both 1 and 2 so that the better parameters are achieved with the acid possessing lower pKa values (a stronger acid). The comparison of the catalytic behaviours of 1 and 2 is discussed in detail considering relevant examples from the literature.
An iron catalyst for oxidation of alkyl C-H bonds showing enhanced selectivity for methylenic sites
Prat, Irene,Gomez, Laura,Canta, Merce,Ribas, Xavi,Costas, Miquel
supporting information, p. 1908 - 1913 (2013/03/14)
Many are called but few are chosen: A nonheme iron complex catalyzes the oxidation of alkyl C-H bonds by using H2O2 as the oxidant, showing an enhanced selectivity for secondary over tertiary C-H bonds (see scheme). Copyright
